Control moment gyroscope arrays, reaction wheel arrays, and other such devices deployed onboard spacecraft for attitude adjustment purposes generate vibratory forces during operation. Vibration isolation systems are commonly employed to minimize the transmission of vibratory forces emitted from such attitude adjustment devices, through the spacecraft body, to any vibration-sensitive components (e.g., optical payloads) carried by the spacecraft. Vibration isolation systems commonly include a number of individual vibration isolators (typically three to eight isolators), which are positioned between the spacecraft payload and the spacecraft body in a multi-point mounting arrangement. The performance of a vibration isolation systems is largely determined by the number of isolators included within the system, the manner in which the isolators are arranged, and the vibration attenuation characteristics of each individual isolator. Vibration isolation system employing three parameter isolators, which behave mechanically as a primary spring in parallel with a series-coupled secondary spring and damper, provide superior attenuation of high frequency vibratory forces (commonly referred to as “jitter”) as compared to vibration isolation systems employing other types of passive isolators (e.g., viscoelastic isolators). The three parameter isolators are advantageously implemented as single degree of freedom (“DOF”) devices, which provide damping along a single longitudinal axis. An example of a single DOF, three parameter isolator is the D-STRUT® isolator developed and commercially marketed by Honeywell, Inc., currently headquartered in Morristown, N.J.
A spacecraft isolation system may also be equipped with a number of launch lock assemblies, which are positioned between the spacecraft and the payload support structure (commonly referred to as a “palette” or “bench”) in parallel with the isolators. During spacecraft launch, the launch lock assemblies maintain the payload support structure in a fixed spatial relationship with the spacecraft. In so doing, the launch lock assemblies shunt significant inertial or shock loads generated during spacecraft launch around the isolators to protect the isolators from damage that might otherwise occur. At a desired juncture after launch, the launch lock assemblies are actuated to allow relative movement between the payload support structure and the spacecraft. For example, in an implementation wherein the spacecraft isolation system includes a number of single DOF, three parameter isolators of the type described above, the isolators may be maintained in compressed state by the launch lock assemblies prior to launch. The isolators are preloaded in their compressed positions and biased toward design or free length positions. When the launch lock assemblies are released, the isolators expand axially into the design position and displace the payload support structure outward from the spacecraft body. The payload support structure, supported by or “floating on” the isolators, is now able to move relative to the spacecraft; and the isolators function collectively to dampen vibrations transmitted between the payload support structure and the spacecraft body.